Manufacture of silver-coated aluminium plates.



UNITED STATES PATENT FFICE.

EDOUARD MARTIN, or PARIS, FRANoE.

SPECIFICATION forming part of Letters Patent No. 673,126, dated April30, 1901.

Application filed July 17, 1900. Serial No. 23,870. (No specimens.)

To all whom it may concern.-

Be it known that LEDOUARD MARTIN, a citizen of the Republic of France,and a resident of Paris, France, have invented certain new and usefulImprovements in the Manufacture of Aluminium Sheets or Plates Coatedwith Silver on One or Both Faces, of which the following is aspecification.

This invention relates to improvements in the manufacture of aluminiumsheets coated with silver on one or both faces, and has for its objectto produce a thorough union of the silver and aluminium and to produce alight plate of metal not easily oxidized and of great brightness.

In carrying out my invention I first clean an ingot of aluminium andpolish it with pumice-stone. I then by means of a solution of sulfate ofcopper, prepared in the common and well-known Way, and a galvanicbattery or other adaptable source of electricity deposit a thin coat ofcopper upon the surface of the aluminium in the common and wellknown wayand in proportion to the thickness of the ingot. The ingot thus preparedis then slightly heated and its surface lightly rolled to prepare it forthe silver. I then by galvanic action in the common and Well-known Waydeposit a coat of silver upon the ingot to prepare it for being moreeffectually welded to a silver plate than if a bare surface or copperwere used. I also prepare plates of silver in the following Way I firstform a body of any adaptable soft material,such as wax or clay. Uponthis I lay a surface of powder which is an electrical conductor,such aspulverized metal, plumbago, and the like substances. Upon thisconducting-surface I deposit by galvanic action a coat of silver. Nhenthis coat of silver has attained suflicient thickness, it can be easilyremoved from the body of soft material. It is then cut of proper lengthand width and cleaned with sea-sand for welding, as will be hereinafterdescribed. The aluminium ingots and the silver plates are now bothheated, each in a separate furnace, each furnace provided with aseparate opening, through which the operator can look and watch themetal while it is being heated, so that they will both attain the properheat for further working at the same time, which in both should be alittle below red heat. The silver plates are then placed upon the ingotswhile both are still hot and conveyed to a rolling-machine. If by anychance the metal while being so conveyed should grow cold, it is to bereheated, with the plate lying on the ingot until both are nearlyred-hot. The temperature may be ascertained by frequent in spection. Theplate and the ingot at this nearly red heat are then rolled togetheruntil the pressure has com pletelyand firmly welded them together. Thisprocess may be performed by applying the silver plate to only one faceof the ingot or both, as may be required, for the galvanic action ifproperly conducted will prepare both faces of the ingot alike. The plateof metal so produced may be afterward rolled to any desired thicknesseither by a hot or cold process; but in either case it must first beannealed. Sheets of metal so formed may be beaten, chased, and workedexactly in the same way as sheets formed of only one metal.

It is obvious that divers useful and ornamental articles may be thusmanufactured, too many to be all mentioned in this specification.

What I claim as my invention, and desire to secure by Letters Patent, is

1. The improved process hereinbefore described of manufacturing sheetsof aluminium,coated with silver,which consists,in cleaning an ingot ofaluminium, polishing it with pumice-stone, laying a thin galvanicdeposit of copper upon its surface as described, heating and softlyrolling the same, laying a galvanic deposit of silver upon the surfaceso formed, heating the plates so formed, placing upon said plates,sheets of silver, obtained by galvanic deposit, as set forth, and heatedas specified, and lastly heating and rolling the whole, until a completewelding of the diiferent plates is efiected, all substantially as andfor the purpose set forth.

2. An improved process, for preparing sheets of aluminium to be coatedwith silver, consisting of cleaning ingots of aluminium, polishing thesame with pumice-stone, laying a galvanic deposit of copper on thesurface thereof as specified,s1ight1y heating the same, ence of twowitnesses, this 22d day of June, softly rolling the surface thereof, andby gal- 1900. I vanic action, depositing a coat of silver upon EDOUARD MARTIN the surface so formed, as described, all subr 5 stantially as andfor the purpose set forth. Witnesses:

In testimony that I claim the foregoing as ERNEST MENUSIER,

my invention I have signed my name, in pres- ANTOINE LAVOIX;

